Bellows pressure relief valve

ABSTRACT

A valve for a reciprocating pump includes a housing, a first chamber, a second chamber, a first valve element, and a second valve element. The housing includes an inlet and an outlet. The first and second chambers are within the housing. The first chamber includes a first valve seat and is fluidly connected to the inlet. The second chamber includes a second valve seat and is fluidly connected to the outlet. The first valve element is disposed in the first chamber and includes a spring-loaded check valve element. The second valve element is disposed in the second chamber and includes a buoyant material.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No.62/269,436 filed on Dec. 18, 2015, and entitled “BELLOWS PRESSURE RELIEFVALVE,” the entire contents of which are hereby incorporated byreference in their entirety.

BACKGROUND

The present disclosure relates to reciprocating pumps, and moreparticularly, to reciprocating pumps with a bellows seal.

In reciprocating pumps, bellows are utilized to create a non-slidingseal to prevent exposure of the working fluid to outside air. To preventunwanted fluid leaks, a backup seal is employed to seal the shaftenclosed by the bellows. However, the backup seal seals the back of thebellows and does not allow the bellows to breathe as the bellows expandsand contracts which can cause cycle fatigue and deformation in thebellows. If a simple breather hole with a screen or mesh is put betweenthe bellows and backup seal, the volume of working fluid expelled may bereduced, but air would be ingested and the pump will no longer continueto operate in the event of a bellows rupture.

SUMMARY

A valve for a reciprocating pump includes a housing, a first chamber, asecond chamber, a first valve element, and a second valve element. Thehousing includes an inlet and an outlet. The first and second chambersare within the housing. The first chamber includes a first valve seatand is fluidly connected to the inlet. The second chamber includes asecond valve seat and is fluidly connected to the outlet and the firstchamber. The first valve element is disposed in the first chamber andincludes a spring-loaded check valve element. The second valve elementis disposed in the second chamber and includes a buoyant material.

A reciprocating pump includes a first housing, a rod, a bellows, anendcap, a valve attached to the endcap, and a passage in the endcap. Thefirst housing surrounds a bellows chamber and a displacement chamber.The rod extends into the reciprocating pump. The bellows is connected tothe rod and to the first housing and includes an interior. The endcap isdisposed on an end of the first housing. The rod extends through theendcap. The valve includes a second housing, a first chamber, a secondchamber, a first valve element, and a second valve element. The secondhousing includes an inlet and an outlet. The first and second chambersare within the second housing. The first chamber includes a first valveseat and is fluidly connected to the inlet. The second chamber includesa second valve seat and is fluidly connected to the outlet and the firstchamber. The first valve element is disposed the first chamber andincludes a spring-loaded check valve element. The second valve elementis disposed in the second chamber and includes a buoyant material. Thepassage fluidly connects the interior of the bellows to the valve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view of a reciprocating pump with a bellowsand a relief valve.

FIG. 2 is a partial cross-section view of the reciprocating pump withthe bellows and bearings positioned in the bellows.

FIG. 3 is a perspective view of a sleeve from the reciprocating pump.

FIG. 4 is a perspective view of a bearing from the reciprocating pump.

FIG. 5 is a perspective view of a seal from the reciprocating pump.

FIG. 6 is a cross-section view of a sleeve with a tri-lobed shape takenalong 6-6 in FIG. 3.

FIG. 7 is a cross-section view of a sleeve with a bi-lobed shape.

FIG. 8 is a cross-section view of a sleeve with a quad-lobed shape.

FIG. 9 is a cut-out cross-section view of the reciprocating pump withbearings positioned in the bellows, taken along 9-9 in FIG. 2.

FIG. 10A is a perspective view of a bearing.

FIG. 10B is a cross-section view of the bearing taken along 10-10 inFIG. 10A.

FIG. 11 is a cross-section view of the relief valve.

FIG. 12 is an exploded view of the relief valve.

FIG. 13A is a perspective view of a conical valve element of the reliefvalve.

FIG. 13B is a cross-section view of the relief valve with the conicalvalve element.

DETAILED DESCRIPTION

Pump (FIGS. 1 and 2)

FIGS. 1 and 2 are cross-section views of reciprocating pump 10. FIGS. 1and 2 will be discussed together.

Reciprocating pump 10 includes housing 12, upper end 13 of housing 12with bellows chamber 14, lower end 15 of housing 12 with displacementchamber 16, cylinder manifold 17, piston 18, throat seal 19, outlets 20Aand 20B, inlets 22A and 22B, conduit 24, rod 26 with shoulder 28 andneck portion 29, sleeve 30, exterior 32 of sleeve 30, collar 34, bellows36 with interior 38 and convolutions 40, nut 42, bearings 44, endcap 46with opening 48 and passage 50, bearing 54, seal 56, and relief valve58. FIG. 1 also includes flow F though reciprocating pump 10.

Reciprocating pump 10 includes a bellows circulation pump configured topump paint and/or other fluids. While paint will be used in thisdisclosure as an exemplar, it should be understood that this is merelyone example and that other fluids (such as water, oil, solvents, etc.)can be pumped instead of paint. In one non-limiting embodiment,reciprocating pump 10 is a 4-ball double acting pump such as any known4-ball pump in the art. In one non-limiting embodiment, reciprocatingpump 10 can include the pump described in “Sealed 4-Ball Lowers”repairs/parts manual which is incorporated by reference in its entirety.(“Sealed 4-Ball Lowers”, Part No. 333022B, Revision B, Graco Inc., May2016). In other non-limiting embodiments, reciprocating pump 10 can be asingle-acting pump or other types of double-acting pumps with or withoutbellows.

Housing 12 is a solid, generally cylindrically shaped and enclosed tube.Housing 12 can include a material such as steel, aluminum, or othermetal materials. Upper end 13 of housing 12 is an upper end of housing12 located on or near an upper portion of housing 12. Bellows chamber 14is a compartment within upper end 13 of housing 12 (as shown in FIG. 1).Lower end 15 of housing 12 is a lower end of housing 12 located on ornear a lower portion of housing 12. Displacement chamber 16 forms acompartment within a lower part of housing 12 (as shown in FIG. 1).Displacement chamber 16 is configured for management and transfer of aworking fluid within displacement chamber 16. Cylinder manifold 17 is acomponent of solid material configured for management and transfer of aworking fluid within cylinder manifold 17. Piston 18 is a piston made ofvarious assembled parts and is configured to pump a working fluidthrough displacement chamber 16. Throat seal 19 is a high pressure sealconfigured to prevent the transfer of fluid across throat seal 19.Outlet 20A is a hollow tube-shaped duct extending from upper end 13 ofhousing 12 and is configured for transferring a fluid out of housing 12,through outlet 20A, and into conduit 24. Outlet 20B is a hollowtube-shaped duct extending from housing 12 and is configured fortransferring a fluid from housing 12 to outside of housing 12. Inlet 22Ais a hollow tube-shaped duct extending from upper end 13 of housing 12and is configured for transferring a fluid from outside of housing 12and into bellows chamber 14 of housing 12. Inlet 22B is a hollowtube-shaped duct extending from housing 12 and is configured fortransferring a fluid from conduit 24 and into housing 12. Conduit 24 isa hollow tube.

Rod 26 is an elongated solid piece of material. Near its upper end, rod26 includes shoulder 28 formed by a step in rod 26. Rod 26 also includeneck portion 29 which forms a portion of rod 26 with a diameter that isinset, or less than, a diameter of the remaining portion of rod 26. Inone non-limiting embodiment, neck portion 29 is located above shoulder28 (as shown in FIG. 2). Sleeve 30 is cylindrical or tubular piece ofsolid material. Exterior 32 is an exterior surface of sleeve 30. Collar34 is a ring of solid material with a feature and/or means for attachingcollar 34 to rod 26. Bellows 36 is a flexible sleeve with convolutions40, which have alternating ridges and valleys along the surface ofbellows 36 allowing bellows 36 to contract and expand within bellowschamber 14 of housing 12. In one non-limiting embodiment, a material ofbellows 36 can be polytetrafluoroethylene, other types oftetrafluoroethylenes, or other materials with abrasion resistantcharacteristics. A cross-section shape of bellows 36 (not shown in FIG.1 or 2) can include a circular or multi-lobed shape.

Nut 42 is a ring of solid material which is threaded. Bearings 44 areformed of an abrasion resistant material such as anultra-high-molecular-weight polyethylene or other types ofthermoplastics and/or polyethylenes. Endcap 46 is a disk of solidmaterial with various openings or bores extending at least partiallythrough endcap 46. Endcap 46 also includes opening 48 and passage 50.Opening 48 is a hole or passage through endcap 46 and extends in anupwards/downwards (up and down in FIG. 2) direction from a bottom ofendcap 46 to a top of endcap 46. Passage 50 is a conduit for thetransportation of a fluid. Bearing 54 is a ring of solid material withabrasion resistant surfaces. Seal 56 is a ring-shaped element withflexible sealing surfaces. Relief valve 58 is a valve for regulating theflow of fluids into and/or out of reciprocating pump 10.

Flow F is a path of fluid flow through reciprocating pump 10. In somenon-limiting embodiments, the fluid of flow F can be a gas or liquidsuch as paint, oil, gas, water, hydraulic fluid, solvent, soap, or otherindustrial fluids.

Reciprocating pump 10 can be connected to and driven by a motor. In somenon-limiting embodiments, reciprocating pump 10 can be connected to apneumatic, hydraulic, or electric motor. Bellows chamber 14 anddisplacement chamber 16 of housing 12 are separated from each other by aportion of housing 12. Piston 18 is attached to a lower end of rod 26.Throat seal 19 forms a seal with rod 26 and is attached to rod 26 suchthat rod 26 is able to move up and down relative to throat seal 19.Throat seal 19 is also affixed to an upper end of lower end 15 ofhousing 12. Outlet 20A is fluidly connected to bellows chamber 14 ofhousing 12. Outlet 20A is fluidly connected to inlet 22B via conduit 24which extends from outlet 20A to inlet 22B of housing 12 fortransportation of a fluid from outlet 20A to inlet 22B. Inlet 22A isfluidly connected to bellows chamber 14 of housing 12. Inlet 22B isfluidly connected to displacement chamber 16 of housing 12.

Rod 26 extends through opening 48 of endcap 46 and into bellows chamber14 of housing 12. A portion of rod 26 also extends partly intodisplacement chamber 16. Rod 26 with its lobed shape interacts withbearing 54 in endcap 46 to prevent relative rotation between rod 26 andendcap 46. Sleeve 30 is connected to rod 26 such that sleeve 30surrounds a portion of rod 26. A portion of sleeve 30 is in contact withshoulder 28 of rod 26. Sleeve 30 is secured to rod 26 with a threadedfastener, bolt, clip, or any other form of mechanical fastener. Sleeve30 mounts over rod 26 and rests on shoulder 28 of rod 26. Collar 34 isattached to rod 26 above sleeve 30 such that collar 34 secures sleeve 30to rod 26 by holding collar 34 against shoulder 28 of rod 26. Collar 34is also attached to rod 26 at neck portion 29 of rod 26. In somenon-limiting embodiments, collar 34 is attached to rod 26 via threadedengagement, a fastener, an adhesive, or any other means of attachmentknown in the art. Rod 26 and sleeve 30 extend through bearing 54.

Bellows 36 is clamped to rod 26 and sleeve 30 by nut 42, such that nut42 compresses and seals the lower end of bellows 36 to sleeve 30 andangular motion between sleeve 30 and bellows 36 is prevented. Bellows 36is affixed between endcap 46 and upper end 13 of housing 12 such thatrelative angular motion between bellows 36 and housing 12 is prevented.Bearings 44 are disposed on sleeve 30 within bellows 36 and are eachradially aligned with one of the convolutions of bellows 36.

Endcap 46 is disposed on and affixed to upper end 13 of housing 12.Passage 50, which extends through a portion of endcap 46, fluidlyconnects interior 38 of bellows 36 to relief valve 58. Bearing 54, whichis disposed between endcap 46 and sleeve 30, is slidably engaged withsleeve 30 such that bearing 54 allows for rod 26 and sleeve 30 to movein and out of housing 12. Bearing 54 is fit into opening 48 of endcap46. A shape of bearing 54 matches a shape of opening 48 in endcap 46.Seal 56 is disposed between endcap 46 and sleeve 30 (or rod 26) suchthat seal 56 prevents transmission of a fluid between rod 26 and endcap46. Relief valve 58 is attached to endcap 46 and can be threadablyengaged with endcap 46. Relief valve 58 is also fluidly connected topassage 50 in endcap 46.

In one non-limiting embodiment, reciprocating pump 10 is assembled byattaching the first end of bellows 36 to the first end of sleeve 30. Thefirst end of bellows 36 is attached to the first end of sleeve 30 bysecuring bellows 36 to sleeve 30 with nut 42 such that nut 42 compressesand seals the first end of bellows 36 to sleeve 30. Sleeve 30 withbellows 36 is slid onto a portion of rod 26. Sleeve 30 is secured to rod26. Sleeve 30 is slid onto rod 26 such that sleeve 30 comes into contactwith shoulder 28 of rod 26. Collar 34 is attached to rod 26 above sleeve30 such that collar 34 holds a portion of sleeve 30 against shoulder 28of rod 26. Sleeve 30 is secured to rod 26 by attaching sleeve 30 to rod26 with a threaded fastener, a bolt, or a clip. Sleeve 30 and rod 26 areinserted into housing 12 of reciprocating pump 10. Endcap 46 with sleeve30 and rod 26 are secured to housing 12 of reciprocating pump 10 with atleast one threaded fastener. The second end of bellows 36 is attached toendcap 46 of housing 12 of reciprocating pump 10. Endcap 46 is securedto housing 12 of reciprocating pump 10 with a threaded fastener.

During operation of reciprocating pump 10, rod 26 with piston 18 isdriven in a reciprocating manner up and down within housing 12. Rod 26and sleeve 30 are mounted such that sleeve 30 moves with rod 26 relativeto housing 12, and sleeve 30 remains stationary with respect to rod 26.Throat seal 19 is mounted in housing 12 such that throat seal 19restricts a passage of fluid between bellows chamber 14 and displacementchamber 16. Bearing 54 and seal 56 provide a seal between rod 26 andendcap 46 as rod 26 reciprocates in and out of housing 12. Theconnection between bellows 36 and sleeve 30 creates a static sealcapable of preventing the working fluid from entering interior 38 ofbellows 36 via a connection point between sleeve 30 and bellows 36.Bellows 36 creates a non-sliding seal with sleeve 30 which prevents aworking fluid of reciprocating pump 10 from exposure to outside air. Asrod 26 is reciprocated into housing 12, bellows 36 expands and thelength of bellows 36 increases. As rod 26 is reciprocated out of housing12, bellows 36 contracts and the length of bellows 36 is reduced.

The use of sleeve 30 allows rod 26 to be a single piece improvingstrength and reliability of rod 26. The configuration of reciprocatingpump 10 does not require complete disassembly of reciprocating pump 10in order to replace bellows 36. Endcap 46 and collar 34 are removed fromhousing 12 and then sleeve 30 along with bellows 36 can be pulled out ofthe top of reciprocating pump 10.

Another advantage of sleeve 30 is that sleeve 30 and bellows 36 can beremoved from reciprocating pump 10 without removing rod 26. For example,if bellows 36 fails in the field, a user can remove collar 34, removeendcap 46, and slide sleeve 30 and bellows 36 out of reciprocating pump10. Bellows 36 is then replaced on sleeve 30 and the assembly is slidover rod 26 and into reciprocating pump 10. The rest of the procedure isreversed to assemble reciprocating pump 10. In this way, rod 26 is notrequired to be removed which translates into not touching the rod andpiston seals which can compromise displacement chamber 16 of pumphousing 12. This drastically simplifies replacement of bellows 36 incomparison to existing designs.

Lobed Sleeve (FIGS. 3-8)

FIG. 3 is a perspective view of one embodiment of sleeve 30 in whichsleeve 30 includes a lobed shape with three lobes 60 that are arrangedaround rod axis A_(R). Lobes 60 can be formed during manufacturing ofsleeve 30. Lobes 60 can be formed such that sleeve 30 and lobes 60include a single piece of material, or lobes 60 can be attached oraffixed to sleeve 30. A cross-section of sleeve 30 includes a lobedshape (see also FIGS. 6-8) which can include at least two lobes such asfor example two, three, four, or more lobes.

Bearing 54, seal 56, and opening 48 of endcap 46 are configured to matewith the lobed shape of sleeve 30 cross-section. Bearing 54 is fit intoopening 48 of endcap 46 and sleeve 30 is fit into bearing 54 such thatendcap 46, bearing 54, and sleeve 30 are configured to prevent rotationof sleeve 30 relative to housing 12.

During operation or assembly of existing reciprocating pumps, the pumprod can rotate relative to the pump housing which can cause bellows 36to deteriorate structurally and performance-wise. Existing solutionsinclude the use of a D-shaped rod with a flat side and small cornerradii which is difficult to manufacture and can be difficult to seal.

The lobed shape of sleeve 30 and corresponding bearing 54, seal 56, andopening 48 of endcap 46 provides rotational stops for preventing sleeve30 from rotating relative to housing 12. Sleeve 30 engages with endcap46 of housing 12 to inhibit sleeve 30 from turning during assembly andoperation of reciprocating pump 10. The lobed shape of sleeve 30 can beeasily ground into sleeve 30 with high precision and a good surfacefinish, both of which are requirements for reciprocating pump 10 andseal 56 to function properly. In particular, a tri-lobed shape givessleeve 30 an inherent centering property because of the three lobes,while still maintaining a minimum corner radius of sleeve 30 that isacceptable for a backup seal in a reciprocating bellows pump such asseal 54 in reciprocating pump 10. The inherent centering property ofsleeve 30 also extends to bellows 36 in that bellows 36 correspondinglyis automatically centered relative to rod 26 and housing 12 due to thelobed shapes of rod 26 and sleeve 30.

An advantage of rotation prevention is that seal 56 forms a sealedinterface with endcap 46 and with rod 26 to prevent fluid from exitingout of housing 12 via the interface between endcap 46 and rod 26. Thelobed configuration of sleeve 30 also allows for better sealing betweensleeve 30 and endcap 46 as compared to a D-shaped configuration or rod26 and/or sleeve 30, as well as allows for more torque to be appliedbetween rod 26 and housing 12 before damage occurs to any of theelements of reciprocating pump 10.

FIG. 4 is a perspective view of bearing 54 from reciprocating pump 10.Bearing 54 is configured to accommodate the lobed shape of sleeve 30. InFIG. 4, bearing 54 is shown to include three lobes 62. In othernon-limiting embodiments, bearing 54 can include a cross-section shapeincluding more or less than three lobes 62 such as two, four, or morelobes.

FIG. 5 is a perspective view of seal 56 from reciprocating pump 10. Seal56 is configured to accommodate the lobed shape of sleeve 30. In FIG. 5,seal 56 is shown to include three lobes 64. In other non-limitingembodiments, seal 56 can include a cross-section shape including more orless than three lobes 64 such as two, four, or more lobes.

In existing pumps, rods and corresponding seals include small cornerradii that make it difficult to provide a seal between rod and seal. Thelobed shapes of sleeve 30 and seal 56 allow for seal 56 to conform tothe rounded corner radii of lobes 60 of sleeve 30 and provide a moresecure seal between sleeve 30 and seal 56 than existing sealconfigurations.

FIG. 6 is a cross-section view of sleeve 30 taken along 6-6 in FIG. 3.Sleeve 30 includes a tri-lobed shape with three lobes 60. Lobes 60 areformed with sleeve 30 as sleeve 30 is machined or manufactured. In othernon-limiting embodiments, lobes 60 can be attached to sleeve 30. Asdiscussed above, the lobed shapes of sleeve 30 and seal 56 allow forseal 56 to conform to the rounded corner radii of lobes 60 of sleeve 30and provide a secure seal between sleeve 30 and seal 56. Additionally,the tri-lobed shape of sleeve 30 provides an inherent centeringproperty, while still maintaining a minimum corner radius acceptable fora backup seal such as seal 54 in reciprocating pump 10.

FIG. 7 is a cross-section view of sleeve 30′. Sleeve 30′ includes abi-lobed shape with two lobes 60′. The bi-lobed configuration of sleeve30′ engages with endcap 46 of housing 12 to prohibit sleeve 30′ and rod26 from turning during assembly and operation of reciprocating pump 10.

FIG. 8 is a cross-section view of sleeve 30″. Sleeve 30″ includes aquad-lobed shape with four lobes 60″. The quad-lobed configuration ofsleeve 30″ engages with endcap 46 of housing 12 to prohibit sleeve 30″and rod 26 from turning during assembly and operation of reciprocatingpump 10.

Bearings (FIGS. 9, 10A, and 10B)

FIG. 9 is a cut-out cross-section view of reciprocating pump 10 takenalong 9-9 in FIG. 2. FIG. 9 shows housing 12, rod 26, sleeve 30,exterior 32 of sleeve 30, bellows 36, interior 38 of bellows 36,convolutions 40, nut 42, and bearings 44.

Bearings 44 are disposed within interior 38 of bellows 36 betweenbellows 36 and sleeve 30. Bearings 44 extend around exterior 32 ofsleeve 30 and are radially aligned with convolutions 40 of bellows 36,for example aligned along a radial direction from rod axis A_(R).Bearings 44 are slidably engaged with sleeve 30 such that sleeve 30 isconfigured to move in an axial direction relative to bearings 44, shownby arrows R_(M), as bellows 36 moves relative to sleeve 30. For example,as bellows 36 contracts and expands, each of convolutions 40 moves in anaxial direction relative to rod 26 and sleeve 30. With each of bearings44 being radially aligned with one of convolutions 40, each of bearings44 moves with convolutions 40 as bellows 36 contracts and expands.

Bearings 44 are placed to prevent bellows 36 from contacting rod 26during compression and expansion of bellows 36. During operation ofreciprocating pump 10, bearings 44 ride up and down on rod 26 to supportbellows 36 and keep bellows 36 from squirming or disfiguring. Preventingbellows 36 from squirming or disfiguring protects bellows 36 from cominginto contact with sleeve 30 which can cause bellows 36 to becomedamaged. Preventing damage to bellows 36 prevents the working fluid frompassing into interior 38 of bellows 36 and causing failure ofreciprocating pump 10.

The number of bearings 44 in reciprocating pump 10 can include one ormore bearings. In one non-limiting embodiment, bearings 44 can begenerally evenly spaced from each other along interior 38 of bellows 36.In other non-limiting embodiments, bearings 44 can be disposed inuniform or non-uniform spacing patterns to account for the length andoperational behavior of bellows 36 and reciprocating pump 10.

FIG. 10A is a perspective view of an embodiment of bearing 44 that isconfigured to mate with a tri-lobed embodiment of sleeve 30. FIG. 10B isa cross-section view of bearing 44 taken along 10-10 in FIG. 10A. FIG.10A and 10B will be discussed together.

Bearing 44 is a snap-ring and includes slit 66, ridge 68, and interiorsurface 70. Slit 66 includes a point of discontinuity in bearing 44.Slit 66 includes a slanted cut along bearing 44. In other non-limitingembodiments, slit 66 can include shapes other than a slanted line suchas a curved, jagged, saw-tooth, or another geometric-shaped interface.Ridge 68 includes a pointed face of bearing 44 which extends generallyradially outwards from bearing 44. Ridge 68 can be formed as a part ofbearing 44 or can be attached to bearing 44.

Interior surface 70 of bearing 44 is an inside face of bearing 44 with across-section shape configured to accommodate the lobed shape of sleeve30. The cross-section shape of interior surface 70 of bearing 44includes a tri-lobed configuration. In other non-limiting embodiments,the cross-section shape of interior surface 70 of bearing 44 can includea lobed shape with two, four, or more lobes. In yet other non-limitingembodiments, the cross-section shape of interior surface 70 of bearing44 can include any shape other than a lobed shape such as for example acircular shape. In such a non-limiting embodiment of interior surface70, three points of contact are formed on the circular interior surface70 (or internal diameter) of bearing 44 with the tri-lobed shape ofsleeve 30 to maintain axial position of bearing 44 without adapting theshape of interior surface 70 to be lobed. Such a configuration wouldforce bearing 44 to be co-axial with rod 26 and/or sleeve 30.

Slit 66 allows bearing 44 to be contorted during installation so as toallow bearing 44 to be inserted into bellows 36. The interface at slit66 allows a portion of bearing 44 to be split and wound inwardly. Duringinstallation of bearing 44 into bellows 36, a diameter of bearing 44 isdecreased by winding bearing 44 into itself. As bearing 44 is woundinwardly, an effective diameter of bearing 44 is decreased. With thedecreased diameter, bearing 44 is inserted into bellows 36. Once alignedwith one of convolutions 40 of bellows 36, bearing 44 is unwoundincreasing the effective diameter of bearing 44. As the diameter ofbearing 44 is increased, bearing 44 is snapped into one of convolutions40 of bellows 36. As bearing 44 snaps into one of the convolutions 40 ofbellows 36, ridge 68 is inserted into one of convolutions 40 of bellows36. With ridge 68 inserted into one of convolutions 40 of bellows 36,bearing 44 is held in place relative to the one of convolutions 40 ofbellows 36 thereby preventing relative axial displacement betweenbearing 44 and convolution 40. As bellows 36 expand and contracts alongrod 26 and sleeve 30, bearing 44 moves along with the one ofconvolutions 40 of bellows 36 to prevent bellows 36 from coming intocontact with sleeve 30.

In another non-limiting embodiment, bearing 44 can interface withbellows 36 by way of dedicated receiver grooves positioned within theconvolutions of bellows 36. The dedicated receiver grooves can include asleeved collar including a groove for receiving bearing 44. Thededicated receiver grooves can be placed within and along theconvolutions 40 of bellows 36 prior to installation of bearing 44 inbellows 36.

Relief Valve (FIGS. 11, 12, 13A, and 13B)

FIG. 11 is a cross-section view of relief valve 58. FIG. 12 is anexploded view of relief valve 58. FIGS. 11 and 12 will be discussedtogether. Relief valve 58 is discussed herein as being used withreciprocating pump 10, however in other non-limiting embodiments reliefvalve 58 can be used with other types of pumps such as diaphragm pumpsor any other statically sealed assemblies.

Relief valve 58 includes housing 72, inlet 74, outlet 76, first chamber78, second chamber 80, passage 81, channels 82, first valve seat 84,second valve seat 86, first valve element 88 with spring-loaded checkvalve element 90 and spring 92, and second valve element 94 with balls96A and 96B.

Housing 72 is a generally cylindrical body of material containing firstchamber 78, second chamber 80, inlet 74, and outlet 76. Inlet 74 andoutlet 76 are tubular portions of solid material extending outwards fromhousing 72. Both inlet 74 and outlet 76 can include threading or otherfeatures for fastening or attachment. First chamber 78 and secondchamber 80 are compartments within housing 72 for the transport offluids such as a liquid or gas. Passage 81 is a fluidic passageextending through a portion of housing 72. Channels 82 are slits, cuts,or passages along and in the wall of second chamber 80. In thisembodiment, first valve seat 84 and second valve seat 86 are O-ringsthat provide sealing surfaces. First valve element 88 includesspring-loaded check valve element 90 and spring 92. Spring-loaded checkvalve element 90 is a ball valve element that is connected to spring 92.Second valve element 94 includes balls 96A and 96B of a buoyant materialsuch as plastic. In other non-limiting embodiments, second valve element94 can include one or more hollow balls, ellipsoids, cones, cylinders,or other shapes.

Inlet 74 of relief valve 58 is attached to endcap 46 of housing 12 andis fluidly connected to interior 38 of bellows 36 via passage 50 inendcap 46. First chamber 78 contains first valve element 88 and firstvalve seat 84 and is fluidly connected to inlet 74 and to second chamber80. Second chamber 80 contains second valve element 94 and second valveseat 86 and is fluidly connected to outlet 76 and to first chamber 78.Passage 81 fluidly connects first chamber 78 and second chamber 80.Channels 82 extend along a portion of the wall of second chamber 80.First valve seat 84 is positioned at an end of first chamber 78 that isopposite from second chamber 80 and is partly disposed in housing 72between inlet 74 and first valve element 88. First valve seat 84includes a shape configured to create a seal with first valve element 88when first valve element 88 comes into contact with first valve seat 84.

Second valve seat 86 is positioned at an end of second chamber 80 thatis opposite from first chamber 78 and is partly disposed in housing 72between outlet 76 and second valve element 94. Second valve seat 86includes a shape configured to create a seal with second valve element94 when second valve element 94 comes into contact with second valveseat 86. Spring-loaded check valve element 90 is disposed in firstchamber 78. Spring 92 of first valve element 88 biases spring-loadedcheck valve element 90 against first valve seat 84 and is connected tohousing 72 at an end of first chamber 78 opposite of first valve seat84. Second valve element 94 is disposed in and contained within secondchamber 80 such that second valve element 94 is able to move freelywithin second chamber 80. Second valve element 94 is centered in secondchamber 80 by housing 72.

In existing pumps, bellows are utilized to create a non-sliding seal toprevent exposure of a working fluid to outside air. To prevent unwantedfluid leaks, a backup seal can be used to seal the pump rod enclosed bythe bellows. However, the backup seal seals the back of the bellows anddoes not allow the bellows to breathe as the bellows expands andcontracts. This can cause cycle fatigue and deformation in the bellows.If a simple breather hole with a screen or mesh were put between thebellows and backup seal, air can ingress through the hole and workingfluid can egress through the hole and the pump would no longer continueto operate in the event of a bellows rupture.

First valve element 88 with spring-loaded check valve element 90 isdesigned to allow fluid to leave interior 38 of bellows 36 and travelpast spring-loaded check valve element 90 while also preventing fluidfrom entering into interior 38 of bellows 36 through relief valve 58.First valve element 88 with spring-loaded check valve element 90 is alsodesigned to let any pressure out of bellows 36 that is substantiallyabove atmospheric pressure to ensure interior 38 of bellows 36 does notget pressurized during the normal cycling of reciprocating pump 10. Ifthe pressure in bellows chamber 14 is below atmospheric pressure, firstvalve element 88 keeps the pump operating after bellows 36 has rupturedby maintaining the position of first valve element 88 against firstvalve seat 84. Interior 38 of bellows 36 can fall below atmosphericpressure during a failure of bellows 36 due to inlet suction of thepump.

Second valve element 94 is used to allow low viscosity fluids such asair to escape from relief valve 58, but in the case of the workingliquid leaving reciprocating pump 10 and entering relief valve 58,second valve element 94 floats in the working liquid pressing secondvalve element 94 against second valve seat 86. Liquid flow from reliefvalve 58 is thereby shut off and fluid is not allowed to leave interior38 of bellows 36. However, since second valve element 94 is only liftedby a fluid that is denser then second valve element 94, second valveelement 94 only checks or closes when there is a liquid present insecond chamber 80. This configuration allows spring-loaded check valveelement 90 in first chamber 78 to let air out of interior 38 of bellows36, and in the event of a failure of bellows 36, second valve element 94prevents the working liquid from escaping relief valve 58.

In one non-limiting embodiment, second valve element 94 of relief valve58 can include two hollow plastic balls such as balls 96A and 96B. Inother non-limiting embodiments, the quantity, size, shape, and materialof second valve element 94 can be selected to provide for desiredbuoyancy and flow characteristics. One of the aspects of hollow plasticballs is that by design, they are very light so they can float and sealrelief valve 58 when liquid is present which may cause issues when airis being bled from bellows 36 via first valve element 88 of relief valve58. The escaping air, if moving fast enough, can lift balls 96A and 96Band cause balls 96A and 96B to seal against second valve seat 86,preventing the air from bleeding off. To address the issue of bleed airpotentially causing second valve element 94 lifting and coming intocontact with second valve seat 86, channels 82 in housing 72 give air apath around second valve element 94 while still keeping second valveelement 94 centered in housing 72. Channels 82 provide passages for airto pass by and/or around second valve element 94.

During a failure or rupture of bellows 36, the configuration of reliefvalve 58 prevents air from entering into reciprocating pump 10 andprevents the working fluid from exiting reciprocating pump 10. Reliefvalve 58 prevents the pressure inside interior 38 of bellows 36 frombecoming excessively high during normal operation of reciprocating pump10, prevents air from being ingested into reciprocating pump 10 ifbellows 36 is ruptured and the pressure inside bellows chamber 14 isbelow atmospheric pressure, and prevents liquid from being pushed out ofreciprocating pump 10 if the pressure in interior 38 of bellows 36 orbellows chamber 14 of housing 12 of reciprocating pump 10 is aboveatmospheric pressure.

FIG. 13A is a perspective view of an alternative embodiment featuringsecond valve element 94′ of relief valve 58. FIG. 13B is a cross-sectionview of relief valve 58 with second valve element 94′. FIGS. 13A and 13Bwill be discussed together.

Second valve element 94′ includes a conical shape and a buoyantmaterial. The top end, as shown in FIG. 13A, includes a shape configuredto engage with second valve seat 86 creating a seal preventing thetransfer of liquid from second chamber 80 and out of relief valve 58.Similar to second valve element 94 discussed with respect to FIGS. 11and 12, second valve element 94′ combined with channels 82 in housing 72allow for air to pass by and/or around second valve element 94′ whichprevents the transfer of air through second chamber 80 from causingsecond valve element 94′ from closing relief valve 58 due to air flowingout of relief valve 58.

While the invention has been described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment(s) disclosed, but that theinvention will include all embodiments falling within the scope of theappended claims.

1. A valve for a reciprocating pump, the valve comprising: a housingwith an inlet and an outlet; a first chamber within the housing, thefirst chamber with a first valve seat and fluidly connected to theinlet; a second chamber within the housing, the second chamber with asecond valve seat and fluidly connected to the outlet and the firstchamber; a first valve element disposed in the first chamber, whereinthe first valve element comprises a spring-loaded check valve element;and a second valve element disposed in the second chamber, wherein thesecond valve element comprises a buoyant material.
 2. The valve of claim1, wherein the second chamber comprises channels extending into thehousing for transmission of a gas past the second valve element.
 3. Thevalve of claim 1 further comprising a spring located in the firstchamber, wherein the spring is in contact with the housing and biasesthe first valve element against the first valve seat.
 4. The valve ofclaim 1, wherein the second valve element comprises a hollow plasticball.
 5. The valve of claim 1, wherein the second valve elementcomprises a hollow cone, ellipsoid, or cylinder.
 6. A reciprocating pumpcomprising: a first housing surrounding a bellows chamber and adisplacement chamber; a rod extending into the reciprocating pump; abellows connected to the rod and to the first housing, the bellowsincluding an interior; an endcap disposed on an end of the firsthousing, wherein the rod extends through the endcap; a valve attached tothe endcap, wherein the valve comprises: a second housing with an inletand an outlet; a first chamber within the second housing, the firstchamber with a first valve seat and fluidly connected to the inlet; asecond chamber within the second housing, the second chamber with asecond valve seat and fluidly connected to the outlet and the firstchamber; a first valve element disposed the first chamber, wherein thefirst valve element comprises a spring-loaded check valve element; and asecond valve element disposed in the second chamber, wherein the secondvalve element comprises a buoyant material; and a passage in the endcap,wherein the passage fluidly connects the interior of the bellows to thevalve.
 7. The reciprocating pump of claim 6 and further comprising: abearing disposed between the endcap and the rod such that the bearing isslidably engaged with the rod; and a seal disposed between the endcapand the rod such that the seal prevents transmission of a fluid betweenthe rod and the endcap.
 8. The reciprocating pump of claim 6 furthercomprising a sleeve attached to the rod, wherein the sleeve surrounds aportion of the rod.
 9. The reciprocating pump of claim 8 and furthercomprising: a bearing disposed between the endcap and the sleeve suchthat the bearing is slidably engaged with the sleeve; and a sealdisposed between the endcap and the rod such that the seal preventstransmission of a fluid between the rod and the endcap.
 10. Thereciprocating pump of claim 6, wherein the second chamber compriseschannels extending into the housing for transmission of a gas past thesecond valve element.
 11. The reciprocating pump of claim 6 furthercomprising a spring located in the first chamber, wherein the spring isin contact with the housing and biases the first valve element againstthe first valve seat.
 12. The reciprocating pump of claim 6, wherein thesecond valve element comprises a hollow plastic ball.
 13. Thereciprocating pump of claim 6, wherein the second valve elementcomprises a hollow cone, ellipsoid, or cylinder.